Chronic sleep disturbances are experienced by 40% to 70% of the oldest people in the population, over 65 years. Light treatment devices are available in the market, but they are expensive, are generally glaring because they use inefficient light sources. Further, they require that users be seated in front of the device for at least 30-60 minutes, reducing compliance rates. The goal of this proposed project is to test the feasibility of an effective, comfortable light-treatment device to affect the circadian system, and improve sleep efficiency of older adults. It has now been established that controlled light-dark cycles can re-entrain the circadian patterns of older people to a more normal wake-sleep cycle (van Someren et al., 1997; Figueiro et al., 2002, 2005), consolidating their rest/activity rhythms and improving sleep efficiency at night. This can potentially delay transition to more controlled environment and reduce falls among older adults. In addition, the circadian system is maximally sensitive to blue light (Brainard et al., 2001; Thapan et al., 2001, Rea et al., 2005). This device will attempt to combine flexibility of use with an effective light source for the circadian system. If successful, this device can be used as a non- pharmacological tool to consolidate sleep and improve sleep efficiency in older people, including those with Alzheimer's disease (AD). Based upon knowledge on lighting technologies, the sleep and circadian scientific literature, and upon empirical research performed by researchers at Rensselaer, it is believed that a headset device using blue light emitting diodes can deliver the correct spectrum, intensity, and duration of light to robustly stimulate the circadian system without providing glare to the user. Six prototypes that can deliver light of the right intensity, spectrum, and duration at the correct circadian time to activate the circadian system will be constructed. The project team will perform literature review, calculations and measurements to document safety of the proposed light-treatment device. Finally, the project team will test whether blue light delivered to the eyes of adults 50+ years using the prototypes will stimulate their circadian systems at night. Blue light will be given to 8 subjects during the dark phase of the circadian cycle to clearly demonstrate their ability to suppress melatonin, which will be used as a surrogate measure of circadian system activation. Subjective responses will be gathered as to comfort and acceptability of wearing the prototype. Once it is shown that this device can be used to activate the circadian system of those 50+ years, clinical trials can be designed to test the effectiveness of this sleep therapy headset for improving sleep quality of older adults. Sleep therapy headset for improving sleep quality of older adults Chronic sleep disturbances are experienced by 40% to 70% of the oldest people in the population over 65 years, which is a rapidly growing segment of the population. The purpose of this proposal is to improve the health and quality of life of older people, by testing the feasibility of an effective, comfortable light-treatment device that can be used to consolidate the rest/activity rhythms of older adults, including those with Alzheimer's disease (AD). Positive results would form an important scientific foundation for home care and institutional procedures and technologies that demonstrably and reliably improve the quality of life for older people, including those with AD. [unreadable] [unreadable] [unreadable]